Suppose that a geneticist discovers a new mutation in Drosophila melanogaster that causes the flies to shake and quiver. She calls this mutation quiver, qu, and determines that it is due to an autosomal recessive gene. She wants to determine whether the gene encoding quiver is linked to the recessive gene for vestigial wings, vg. She crosses a fly homozygous for quiver and vestigial traits with a fly homozygous for the wild-type traits, and then uses the resulting F1 females in a testcross. She obtains the flies from this testcross.
Phenotype | Number of flies
vg+ qu+ | 230
vg qu | 224
vg qu+ | 97
vg+ qu | 99
Test the hypothesis that the genes quiver and vestigial assort independently by calculating the chi-squared, X^2, for this hypothesis. Provide the X^2 to one decimal place.
X^2 =
Does the X^2 value support the hypothesis that the quiver and vestigial genes assort independently? Why or why not? Use the partial table of critical values for X^2 calculations to test this hypothesis.
No, the X^2 = value indicates that the observed progeny are significantly different from what would be expected with independent assortment of the two genes.
No, the X^2 = value indicates that there are too many phenotypes for independent assortment.
Yes, the X^2 = value indicates that the genes vestigial and quiver assort independently.
Yes, the X^2 = value indicates that the observed and expected number of progeny are equal in number.